Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
U.S. statutory tax benefit	$ (3,699,000)	$ (2,688,000)	$ (4,586,000)
Partnership income (federal) not subject to tax to the Company	996,000	904,000	1,868,000
Foreign withholding tax	91,000		79,000
State taxes (net of federal benefit)	(14,000)	(13,000)	134,000
Research and development tax credit	(173,000)	(138,000)	(231,000)
Other	10,000	75,000	(81,000)
Change in valuation allowance	2,904,000	1,860,000	2,917,000
Provision for income taxes	$ 115,000	$ 0	$ 100,000
Effective income tax rate	(0.70%)	0.00%	(0.50%)